• Agencies that receive classified material can pass along that information to other people and agencies holding appropriate security clearances without first getting approval from the agency that originally classified the material.

• Agencies must not classify information — or at least classify it at a lower level — if there is "significant doubt" about the need to keep a record secret.

• Agencies must remove from their classification guidelines any procedures that might lead to the inappropriate classification of information.

• Agencies must adopt standard formats for classified electronic documents so classified information can be more easily disseminated.

• Agencies must create unclassified versions of documents when possible to allow for broader intelligence sharing.

• Agencies cannot keep information secret for more than 75 years. Also, Obama clarified what information can be exempt from automatic declassification after 25 years. Those exceptions include information that would reveal methods of intelligence gathering, intelligence sources or war plans.

"I think the order will invigorate the declassification of historical records, and I hope that it will also prompt a new way of thinking about the classification of current records," Steven Aftergood, director of the Project on Government Secrecy at the Federation of American Scientists, said.

The review of current guidelines "should lead to a reduction in current classification activity, because it "requires each classifying agency to ‘scrub' its classification guides to eliminate obsolete requirements that no longer correspond to a valid threat," Aftergood said.

Obama also ordered efforts to declassify hundreds of millions of pages of classified material be speeded up. In charge of the effort will be a new agency — the National Declassification Center at the National Archives and Records Administration — which will check with agencies responsible for classifying materials to ensure they are no longer sensitive before declassifying them.

The center confronts a backlog of 400 million pages of classified material to review for declassification — Obama has said he wants that completed by the end of 2013, according to Michael Kurtz, acting center director and assistant archivist for record services at Archives.

To handle the work, the Archives plans to hire more people, Kurtz said. The new center could be up and running as early as next week, he said.